Boiler-furnace and chain-grate stoker therefor.



Patented Nov. [3, I900.

R. m. SNYDER. BOILER FURNACE AND CHAIN GRATE STOKER THEREFOR.

(Application filed A t. 27, 1900.

(No Model.)

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No.'66|,675.' v Patented Nov. I3, I900. R. M. SNYDER.

BOILER FURNACE AND CHAIN GRATE STOKERTHEREF'OR.

(Application filed Apr. 27, 1900.) (No Model.) 2 Sheets-Sheet 2.

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I NITED STATES ATENT 0FFlCEa ROBERT M. SNYDER, OF VANDERGRIFT, PENNSYLVANIA.

SPECIFICATION forming part of Letters Patent No. 661,675, dated November 13, 1960.

Application filed April 27, 1900- SerialNo.14,592. (No model.)

To all whom it may concern:

Be it known that 1, ROBERT M. SNYDER, a resident of Vandergrift, in the county of Westmoreland and State of Pennsylvania, have invented a new and useful Improvement in Boiler-Furnaces and Chain -Grate Stokers Therefor; and I do hereby declare the following to be a full, clear, and exact description thereof.

My invention relates to boiler-furnaces and chain-grate stokers therefor,and has for its object the improvement of devices of this character in details of construction which make a more efficient boiler-furnace and chain-grate stoker.

In boiler-furnaces as heretofore constructed the stoker-chamber has been separated from the coal-hopper in front of the same by a water-gatethat is, one cored out to allow water to circulate therethrough.

One object of my invention is to dispense with the water-gate and to provide means for both cooling the gate and spraying the coal, and to this end I separate the coal-hopper from the stoker-chamber by means of a solid gate so constructed as to hold the water coming from a continuous spray, thereby effectually cooling the gate, the water thereafter running down into the coal-hopper and moistening the coal therein, therebyinsuring more perfect combustion.

In the usual chain-grate stokers the rear shaft for the stoker is provided with carriers for the stoker-chains; but as the stoker passes over said carriers it opens up and allows ashes and clinkers to fall into the inside of the stoker, and, furthermore, the intense heat causes the shaft to bend and sag. Another object of my invention is to overcome this defeet, and to this end I provide a hollow shaft for supporting the rear end of the stoker, said shaft being of sufficient size to contact with the carriers for the grate-bars, thus preventing ashes and clinkers from falling into the stoker, and at the same time the hollow shaft is much more rigid than a solid one, for the reason that air can circulate therethrough and keep it cool. To prevent back draft, I provide a fixed diaphragm in a single piece situated below the rear shaft of the stoker and cut away to fit over the ash-conveyor.

A further defect in the present stokers exists in the fact that the grate-bars are slid endwise upon the grate-carriers, so that if one of said bars becomes broken or burned outitcannot be removed without first removing other bars on the carrier. A further object of my invention is to overcome this defect and provide grate-bars which are independently detachable from the carrier; and to this end it consists of a carrier in the form of an anglebar, with the grate-bars independently secured thereto by means of cotter-pins.

A further defect in the present chain-grate stokers exists in the form of the grate-bars, which are such that the ends of the cross-bars are exposed to the intense heat and therefore quickly burn off. It has been proposed to overcome this defect by making grate-bars with exceedingly short cross-bars; but this makes the grate too compact and prevents the proper draft therethrough. A further object of my invention is to overcome this defeet and provide a grate-bar which is open, so as to allowa good draft therethrough, but which will not be readily burned out; and to this end it consists of a grate-bar having its cross-bars united at their ends by side bars, which protect the ends of the cross-bars from the intense heat of the furnace.

I will now describe my invention more fully, referring to the accompanying drawings, in which Figure 1 is a vertical longitudinal section of my improved boiler-furnace and chaingrate stoker therefor. Fig. 2 is a front elevation with the lower part of the furnace and stoker in vertical section on the line 2 2, Fig. 1. Fig. 3 is a side view of the front part of the furnace with the lower part thereof in section. Fig. 4 is a side-elevation of a gratebar carrier with the bars secured thereto. Fig. 5 is a longitudinal section of a portion of the chain-grate stoker, and Fig. 6 is a perspective view of my improved grate-bar.

The furnace comprises the usual combustion-chamber 1, leading to the boiler 2, which, as shown, is of the vertical type, but this forms no part of my invention, and it is obvious that any type of boiler could be used. Beneath the combustion -chamber 1 is the stoker-chamber 3, which is provided with the rear wall 4, the rear arch 5, and the front or coking arch 6, all as is usual in this type of furnaces. Therear arch 5 is supported by the angle-iron 7, having one web lying be-.

neath said arch and the other web resting against the front of the rear wall 4. The rear arch is composed of long bricks or tiles, as shown, which rest on the rear wall 4 and on the horizontal web of the angle-iron 7' and project beyond the front edge of the latter. By this construction the projecting ends of the tiles composing said arch are exposed to the intense heat of the furnace, while the angle-iron supporting the same is somewhat protected therefrom, so that it remains rigid and keeps the arch from sagging. The front or coking arch 6 is supported by a similar angle-iron 8, having one web lying underneath said arch and the other web lying against the front of the arch, forming a face plate therefor. By this construction the rear and front arches are greatly strengthened and under the intense heat of thefurnace do not crumble and break down as in the old form.

To quickly chill thefire when steam blows off, I provide a cold-air door 9 in an opening 10, placed in the front face of the furnace above the cokingarch 6 and in front of the rear edge of said arch. The cold-air door is provided with a suitable aperture 11, covered by means of a swinging gate or door 12, through which opening the interior of the furnace-chamber and boiler can be observed at any time. chill the fire, it is only necessary to open the door 9, allowing air to pass into the chamber above the fire, thereby quickly chilling the same.

In front of the furnace, on either side, are the housings 13 14, between which is the inclined chute 15, forming the front wall of the coal -'hopper, which is separated from the stoker-chamber 3 by means of the sliding gate 16, which is raised and lowered by means of chains 18, passing over segments 19, secured to a shaft 20, running across the front of the furnace, which shaft may be operated in any suitable way, as by means of a wormsegment 21, secured to said shaft, which is engaged by a worm on a shaft 22, provided with a hand-wheel 23. By the means described the gate 16 can be raised or lowered as desired to regulate the amount of coal fed into the stoker-chamber.

The gate 16 is formed of a'single integral cast piece, and to keep it cool and prevent it burning out it is provided on its outer face being connected through an ordinary valve 27 with a water-supply pipe 28, extending across the face of the furnace, and in case two or more furnaces are placed side by side When it is desired to quickly said water-pipe 28 will extend across the front of all the furnaces in the battery. The wa ter falling upon the front of the gate 16 is held in the chambers 25 to a considerable extent, thereby effectuallycooling said gate, after which it runs down into the coal-hopper, moistening the coal therein. It is well known that combustion is greatly aided by wetting the coal, and I have found that by continuously spraying the coal with water just before it enters the furnace combustion is aided to such an extent as to entirely consume the smoke, and inasmuch my stoker is continuously operating and the spraying is likewise continuous I have provided a furnace and stoker which practically produces no smoke, except when it becomes necessary to break up the surface of the burning coal on the grate, as by means of a suitable bar.

In the usual water-gate employed the water after circulating through the gate and becominghcated-isdischargedinto the sewer,and the heat held thereby is lost. With my gate, however, no heatis lost to the furnace, for the water after being heated by contact with the gate 16 falls on the coal in the hopper and is at once conveyed into the furnace and aids the combustion of the coal. The continuous spraying of the coal with hot water just as the coal passes into the furnace is an important feature of my furnace, and it is largely due thereto that the combustion is so'nearly perfect as to entirely consume the smoke.

The stoker-chamber 3 is provided on each side with a rail 29, upon which run the Wheels 30 of the carriage 31 of my improved chaingrate stoker 32, which is carried by the usual front shaft 33, the bearings of which maybe suitably adjusted, as by means of the screws 34, to keep the chain grate taut. At the rear end the chain grate passes over the hollow shaft 35, which has its interior open to the air through the journals thereof and which is made of sufficient size to contact with the lower surface of the grate-bar carriers 57, here inafter described, so that as the chain grate opens upin passing around said shaft ashes and clinkers will fall nst the surface of the shaft and be immediately deflected outward,

so as not to fall into the interior of the chai grate.

Beneath the stoker-chainber is the ash-conveyer 36, which consists of an endless screw running longitudinally of the stoker-chamber and serving to convey the ashes from the rear end thereof into a pit 37 in front of the furnace. The conveyer 36 is suitably journaled, as at 38, at its rear end, and at its forward end is journaled in a box 39, secured to the lower side of an angle-iron 40, running across the ash-pit. This leaves the forward end of the'stokerentirely free on its lower side, so that the ashes will not become clogged under the same, but can be forced freely into the ash-pit. On the forward end of the conveyer-shaft I secure a sprocket-wheel 11, which is connected by a sprocket chain 42 ICC with asprocket-wheel 43 on a counter-shaft 44, journaled in suitable bearings secured to the housing 13. Also journaled in bearings secured to the housing 13 is a shaft 45, provided with a pulley for the driving-belt 46, coming from any suitable source of power, said shaft 45 being also provided with. a worm 47, meshed with a worm-wheel 48, secured to the oountershaft 44. The counter-shaft 44 is also provided with a worm 49, meshing with a worm-wheel 50, secured to the front shaft of the chain-grate stoker for driving the same. By the means described the ashconveyer is driven from the same source of power that drives the chain-grate stoker, and said means are simple and leave the front of the furnace entirely unobstructed.

The chain-grate stoker comprises the chainlinks 51, which are forked at their ends, as shown at 52 53, and are connected to each other by means of pivot-pins 54, on which, between the forks of the links, are journaled suitable rollers 55, which run on the guiderails 56, suitably secured to the stoker-carriage 31. Secured to each chain-link 51is an angle-bar 57, which constitutes the carrier for the grate-bars, said angle-bar resting upon a fiat face of the link and bearing against the vertical wall of a projection 58 on said link. The links are provided with lateral projections 59, to which the angle-bars 57 are secured by means of bolts 60. Each gratebar comprises the cross-bars 61, having their ends united by the side bars 62, and two depending webs 63,secured to the side bars, said webs straddling the vertical member of the angle-bar carrier 57 and being secured thereto by means of a cotter-pin 64. The side bars 62 of the grate-bars protect the ends of the cross-bars 61 from the intense heat and prevent the same from being burned off, thereby greatly increasing the life of the grate bars. Each grate-bar is independently removable from the carrier 57 by merely removing the cotter-pin 64, the construction being such that each bar can be removed without disturbing an adjacent bar.

To prevent back draft, I provide a diaphragm 65, which consists of asingle integral piece fixed in position and cut away, as at 66, to fit over the ash-conveyer 36. The diaphragm 65 is preferably fixed in position by being hung over the rear axle 67 of the stokercarriage 31 and has its upper edge curved, as shown at 68, and lying in close proximity to the lower surface of the chain-grate stoker and serving to brush off any clinkers that may adhere thereto. By means of this construction back draft is largely prevented.

The operation of my improved chain-grate stoker will be readily understood from the foregoing description and does not need further description;

By the several improvements above enumerated I provide an efficient boiler-furnace provided with means for not only keeping the front gate cool, but also at the same time continuously spraying the coal, so that combustion is greatly aided thereby. The construction of the chain-grate stokeris such that back draft is largely prevented, ashes and clinkers prevented from falling on the inside of the stoker, the life of the gratebars largely increased, and which allows of the removal of a grate-bar independently of the others when the same becomes broken or defective.

What I claim, and desire to secure by Let ters Patent, is-

1. In a boilet'furnace,the combination with the grate, of a screw ash-conveyer located below the same, the ash-pit in front of the furnace, a bar extending across said pit, and bearings for the front end of the ash-conveyer shaft secured to the lower side of said bar, whereby the space below the conveyer is left unobstructed.

2. In a boiler-furn ace,the combination with a furnace-chamber, of the gate for closing said chamber, said gate comprising a casting provided with horizontal ribs on the outer face thereof forming recesses, and means for spraying water on the outer face of said gate.

3. In aboiler-furnace,the combination with the stoker and chamber therefor, of the coalhopper located in front of said chamber, the gate separating said chamber and the coalhopper, and means for spraying water on the outer face of the gate, whereby the same is cooled and the coal suitably moistened.

4. In abOilerfurnace,the combination with a chain-grate stoker, the chamber in which said stoker is located, of the endless ash-conveyer underneath said stoker, and the fixed diaphragm at the rear end of the stoker-chamber and fitting over the endless ash-conveyor,

said diaphragm having its upper edge curved and lying in close proximity to the lower side of the chain-grate stoker.

5. In a boiler-furnace,the combination with the chain-grate stoker of the carriage on which said stoker is mounted, the endless ash-conveyer underneath said stoker, and the fixed diaphragm hung on the rear axle of the stokercarriage and fitting over the endless conveyer to prevent back draft.

6. In a chain-grate stoker, the combination with the chains therefor, of the grate-bar carriers secured to the chain-links, and the enlarged rear hollow shaft for said stoker, said shaft being of such a diameter as to contact with the lower sides of the grate-bar carriers.

and thereby prevent ashes falling inside the stoker.

7. In a chain-grate stoker the combination with the chain-links, said links having flat horizontal faces and vertical projections, of the angle-bars secured thereto and having one flange resting on the flat faces of said links and the other flange bearing against the vertical projections, and the grate-bars independently and detachably secured to said angle-bars.

8. In a chain-grate stoker, the combination with the chain-links, said links having fiat ing ends are avoided and means on said grate bar whereby the same may be secured to the carrier-bar. I

10. grate-barforchain-grate stokers,comprising the body portion having cross-bars, side bars uniting the ends of the cross-bars, said side bars and the end cross-bars having straight outer faces whereby projecting ends are avoided, and depending webs uniting the side bars for securing the grate-bar to the carrier-bar.

In testimony whereof I, the said ROBERT M. SNYDER, have hereunto set my hand.

ROBERT M. SNYDER.

Witnesses:

F. W. WINTER, ROBERT C. TOTTEN. 

